A former interior minister was sworn in as Malaysia's premier on Sunday, marking the return of a scandal-mired regime to power after the last government's collapse but ex-leader Mahathir Mohamad slammed the move as illegal. Muhyiddin Yassin took the oath of office at the national palace in Kuala Lumpur, capping a week of political turmoil following the collapse of the former ruling coalition and Mahathir's resignation. sr-jsm/qan